A water mass found in the Southern Ocean between the Subtropical Front (STF) and the Subantarctic Front (SAF) and above the salinity minimum of the Antarctic Intermediate Water (AAIW). At the surface the SSW is fresher than the surface waters of the Polar Frontal Zone (PFZ) in the Drake Passage, although by the time it reaches the Greenwich Meridian surface salinities are 0.3–0.4 higher than in the Drake Passage and more saline than those in the PFZ. Below the surface the SSW shows monotonically decreasing temperature as well as a maximum in salinity and a minimum in oxygen, both of the latter induced by the underlying AAIW.